含弱面岩体拉伸破坏形式及声发射特性研究

Experimental Study on the Acoustic Emission Characteristics and Failure Mode of Rock Masses with Weak Plane

金属矿山开采过程中的弱面岩体工程结构极易发生拉剪破坏。为了探究含弱面岩体支护方式与弱面角度的关系,对预制弱面的砂岩进行不同角度的抗拉试验。结果表明:①含弱面拉伸试验试样主要有2种破坏形式,剪切拉伸复合破坏和拉伸破坏;②弱面深度为10 mm,弱面与加载方向的夹角为70°时,预制弱面试件能承受的抗拉强度最大,当预制弱面深度增大时,圆盘试件承受的峰值抗拉强度会随着角度前移;③弱面角度会影响试件劣化过程,当弱面深度为15 mm,弱面与加载方向为50°时,试件会发生突然性断裂,具有一定的岩爆倾向性;④含弱面岩体破坏模式与其内部的不同角度弱面有密切关系。进行室内含预制弱面试件抗拉强度实验,可为含弱面岩体的现场施工提供指导建议。

The engineering structure of rock mass with weak plane in the mining process of metal mine is easy to be damaged by tension and shear.In order to explore the relationship between the support mode and the angle ofweak rock mass,the tensile tests at different angle are carried out for sandstone with weak plane.The results show that:①There are two kinds of failure modes in thesandstone specimen with weak plane,that is,shear tensile failure and tensile failure;②When the angle between the weak plane and the loading direction reaches 70°,the tensile strength of the precast weak plane specimen with 10 mm is maximum;when the depth of the precast weak plane increases,the peak tensile strength of the disc specimen will move forward with the angle;③The angle of weak plane will affect the deterioration of the specimen;when the weak plane and the loading direction are around 50°,the 15 mm specimen will break suddenly,with a certain tendency of rockburst;④The failure mode of the rock mass with weak plane is closely related to its internal weak plane of different angles.The tensile strength experiment for the indoor prefabricatedweak plane specimencan provide guidance for the field construction of the rock mass with weak plane.